Rotary pump and engine



C. McK. SPARROW.

ROTARY PUMP AND ENGINE.

APPLICATION FILED NOV-Z9. I920.

Patented Mar. 7, 1922.

gdwmd UNITED STATES smear orricn.

GHABLES MCK. SPARROW, OF BUFFALO, NEW] YORK.

ao'rnar runs Ann anemia.

Specification of Letters Patent.

Patented Mar. 7, 1922,

Application filed November 29, 1920. Serial No. 426,9.

useful Improvements in Rotary Pumps and Engines, of which the following is a specification.

This invention relates to pumps and motors of thetype in which one or more pistons move in an annular chamber proseparated by an abutment member adapted to permit the pistons to pass without permit-ting communication between the inlet and exhaust ports, and my object is to devise a pump or engine of this type which will be easy to construct, eflicient in operation, and which will possess great durability.

I attain my object by means of the constructions hereinafter described and illustrated in the accompanying drawings in which-- Fig. 1 is a side elevation of my improved pump with one side of the casing removed;

Fig.2 a cross section of the same;

Fig. 3 a side elevation of part of the same showing the parts in a difl'erent position.

In the drawings like numerals of reference indicate corresponding parts in the diiferent figures.

In the specification and claims I refer to the device as a pump, but it will be understood, of course, that like most rotary v pumps, it may be used as well as a motor.

The pump comprises two main parts, a stator 1 and a rotor 2, whlch form between them an annular fluid space 3. The periphery of the rotor revolves against roller bearings 4 carried by the side members 5 of the stator. On the inner periphery of the rotor is formed the internal gear wheel 6. The central disk-shaped part 7 of the stator is suitably recessed to receive the rotary abutment member 8, on the periphery of which are formed the gear teeth 9 meshing with the internal gear wheel 6 of the rotor. The abutment member is rotated by means of the drive shaft 10 to which it is secured. The rotor carries one or more radial pistons 11, which are adapted to pass through a recess 12 in the abutment as the parts rotate. The proportioning of the abutment and rotor and the shaping of the pistons form important features of my invention, as on them depends the ease of manufacture and. the

efficiency of the device. The diameter of the pitch circle of the gear teeth 9 is exactly one-half of the diameter of the pitch circle of the internal gear wheel 6. From this it? follows that as the one part rotates on the. other, any po'int 1n the pitch circle of the in a straight line gear teeth 9 will move radially of the rotor. The edges 13 of the mouth of the recess 12 are therefore formed on the pitch circle of the gear teeth 9, and

planes'radial of the rotor. The edges 13 will thus maintain contact with the faces of the piston from the time they come into (:0- operation until they pass out of co -operation, as will be seen on reference to the drawings. The inlet port 14 and the outlet port 15 are symmetiically arranged with reference to the axis of the shaft 10 of the abutment member and have their adjacent edges separated by a distance not substantially greater than the width of the recess 12, (see Fig. 3.) This point is of importance, as if the recess overlaps the inlet and outlet ports, direct passage of the fluid from one to the other would take place, which would result in inefficient operation of the pump, where as if the recess is materially less in width than the distance separating the adjacent edges of the ports fluid will be trapped in the recess, and as the fluid is usually imcompressible, the pistons entering the recess tend to exercise pressure on the fluid, which is liable to burst the pump.

The operation of the device will be readily seen in view of the above description and on inspection of the drawings. The shaft 10 is suitably driven and the abutment member thereby rotated. The abutment member, through the medium of the'gcars 6 and 9, actuates the rotor causing the pistons to travel round the fluid space 3. Fluid is thus drawn in through the inlet port and expelled through the outlet port, the abutment member at all times preventing direct communication between the two ports. v The pistons pass through the recess in the abutment member, the edges of which by contact with the faces of the pistons assist in maintaining the seal when the extent of mesh bethe faces of the pistons 11 are formed vided with an inlet and an outlet port andtween the gears is least as is necessarily the necessary 'bemveen rontacaing .wzehii'vdy movusual 1311B ELY).

imp surfrnces as 15;

' I u W hat l chum as my mventwn 1s: 1" A rotary pump comprlsmg a sizrtor and lean 11g into the fluid space at adjacent pmnts.

2. A pump e01 structed set forth in claim 1 in which the edges 0' fhg mouth of the recess in the rotary abutment adapt-- ed 10 maintain contact with the; rad. 4 1 faces;

of the pistnn as the the recess" 3. A pump cousins m1 claim 1 in which the adjarcm' pox-as are :sagaratecl by zi' sizntia lly than the recess.

A pump constructed as claim 1 in which the fidg the recess in the rotary a I are L adml i or the pis'tm as the I the reuess and in which of H1:- portf sci subatuniial13y Ufihfiil recsss.

grrad at B October,

7 Wifinessef 

